Source: BBC Radio 4: Today Programme
Date: 09/01/2012
EventDr Luke Skinner on why he's "not proclaiming good news that we've avoided an ice age" 
Attribution: BBC Radio 4

  • John Humphrys Presenter, BBC Radio 4 Today programme
  • Luke Skinner: Palaeoclimatologist, Department of Earth Sciences, Cambridge University

John Humphrys: Now, here's a bit of good news about global warming - it has saved us from another ice age. Dr Luke Skinner of Cambridge University is the man who's been doing this research. He's on the line - good morning to you.

Luke Skinner: Good morning.

John Humphrys: I didn't know we were going to have another ice age.

Luke Skinner: Well, I should say straight off that our study's not proclaiming good news that we've avoided an ice age, but more that if we were trying to avoid an ice age, we've tried a bit too hard.

John Humphrys: Oh right, so it's bad news.

Luke Skinner: It's bad news.

John Humphrys: It always is, on this programme!

Luke Skinner: That's right.

John Humphrys: [Laughs] So let's deal with the second thing first. Are we heading for another ice age? 

Luke Skinner: No, we would argue, not, and I - this is an idea that's been around for a long time. It's pretty clear, based on current CO2 levels, that the natural, sort of, forcing of the climate by seasonality changes, and so on, is not enough to override our influence. And it's also been suggested that even if we hadn't interfered with the climate as much as we have, over the last 200 years, we might still have avoided a climate swing into a glacial state -

John Humphrys: Right, but not because of anything we do, or did, just because that's just not the way it's going to happen...

Luke Skinner: Well, it may be something that we, as a species, have done. Some people have argued that the subtle rise in CO2 across the current interglacial was due to very moderate but nonetheless anthropogenic impacts on atmospheric CO2 - 

John Humphrys: Man-made, in other words, yeah - 

Luke Skinner: Yep. Yeah. 

John Humphrys: All right.

Luke Skinner: Through farming, and so on. But - and we would - our study's arguing that that subtle drift - whether it was due to humans or not, could have been enough to avoid a glaciation -

John Humphrys: Right. But what you're now saying is that we have gone so far, we have pumped so much CO2 into the atmosphere - man-made stuff, that is - that it's dangerous. 

Luke Skinner: Well, yes. I mean that's - that's the subject of a lot of work - not in particular our study that we've done just now - but yeah, that's pretty clear from a whole host of numerical modelling studies. Even, you know, basic physical arguments on - to do with energy balance and how so much CO2 causes so much radiative imbalance, and you can think about the feedbacks that kick in. We're definitely warming. I think the story has, kind of, piqued a lot of interest because we might be afraid of entering into a glaciation and so it's great - we've avoided a glaciation - but I think the thing down the line is, if anything, the study, kind of, suggests that the climate system's quite sensitive to quite small changes in CO2, let alone the huge change that we've been responsible for, over the last 200 years.

John Humphrys: Luke Skinner, thank you very much.